SUS304奥氏体不锈钢TIG焊电弧增材制造工艺优化

Optimization of TIG arc additive manufacturing process for SUS304 austenitic stainless steel

为探索SUS304奥氏体不锈钢TIG焊电弧增材制造的最佳工艺窗口,采用不同沉积工艺参数对SUS304不锈钢进行单道多层墙体成形试验,试验通过改变电弧移动速度、送丝速度和层间冷却时间,研究其对墙体平均宽度和高度的影响,并考察墙体的金相显微组织和力学性能。结果表明,当热输入保持不变时,电弧移动速度和送丝速度相匹配,才能保证沉积过程的稳定;在保持热输入不变的情况下,随着电弧行走速度的增加,沉积层平均宽度从10.54 mm减小到7.5 mm,平均高度从6.75 mm减小到4.16 mm;随着送丝速度的增加,沉积层的平均宽度和高度均增加,其高度增加大约1 mm;随着层间冷却时间的增加,沉积层平均宽度明显增加,从层间冷却时间为2 min的10.54 mm增加到5 min的11.6 mm,高度变化不大,均在6.5 mm左右;沉积墙体的显微组织出现明显的方向性,主要由大量奥氏体和少量铁素体组成;相比于SUS304母材而言,x和z方向的抗拉强度均有所下降,约为母材的82.5%,且x方向的断后伸长率大于z方向。

To explore the optimal process window range for TIG arc additive manufacturing of SUS304 austenitic stainless steel,single-pass multilayer wall forming tests were designed and conducted on SUS304 stainless steel using different deposition process parameters.The experiments were conducted to study the effects on the average width and height of the walls by varying the arc travel speed,wire feeding speed and interlayer cooling time,and to investigate the microstructure and mechanical properties of the thin-walls parts.The test results show that when the heat input is kept constant,the arc travel speed and wire feeding speed should match to ensure the stability of the deposition process.when kept the heat input constant,the average width of the deposited layer decreases from 10.54 mm to 7.5 mm and the average height decreases from 6.75 mm to 4.16 mm with the increase of the arc travel speed;the average width and height of the deposited layer increase with the increase of the wire feeding speed,and its height increases about 1 mm;With the increase of interlayer cooling time and the increase of the interlayer cooling time,the average width of the deposited layer increased significantly,from 10.54 mm at 2 min to 11.6 mm at 5 min,and the height did not change,which was around 6.5 mm.The microstructure of the deposited wall shows clear directionality,mainly composed of a large amount of austenite and a small amount of ferrite.Compared to the SUS304,the tensile strength in both x and z direction is reduced to about 82.5%of that of the substrate,and the elongation in the x direction is greater than that in the z direction.